Anhydrous products having improved wettability characteristics

ABSTRACT

Water-wettable anhydrous products, such as the powders and creams used in cosmetic and drug products, are admixed with 20% to 60% by weight, based on the weight of the total formulation, of a powdered polyethylene or powdered polypropylene polymer, to improve wettability characteristics. Denture adhesive powders prepared from an anionic/cationic adhesive combination, together with the powdered polyethylene or polypropylene polymer display particularly improved properties. The polyethylene or polypropylene polymer may also be admixed with other anhydrous products including dentifrices, vaginal powder sprays, and the like. Low molecular weight polyethylene powder, with an average molecular weight of from 1,000 to 3,500, is suitable for use in products of the invention. For the polypropylene, a molecular weight of from 120,000 to 350,000 is specified. The powdered polymers have a particle size of less than 422 microns.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of United States Ser. No. 302,162, filed Oct. 30, 1972, now U.S. Pat. No. 3,878,138.

BACKGROUND OF THE INVENTION

Many cosmetic and drug products are formulated as anhydrous powders and creams to protect the particular ingredients in the formulation as well as for convenience in manufacturing, packaging, storage and handling. However, since most of these products depend upon water for actual utility, any difficulties encountered in wetting the preparation at the time of use greatly detract from the overall consumer acceptance of the product.

Such is the case with many anhydrous dental preparations including denture adhesives, dentifrices, and the like. Similar problems are frequently encountered with products such as anhydrous vaginal powder spray formulations.

It has now been found that the addition of a powdered polyethylene or polypropylene polymer to such anhydrous powder and cream preparations greatly enhances the wettability characteristics of the preparation.

SUMMARY OF THE INVENTION

Anhydrous powder and cream formulations containing from 20% to 60% by weight, based on the total weight of the preparation, of a powder polyethylene or a powdered polypropylene polymer having a particle size of less than 422 microns, have superior wettability characteristics. Suitable polyethylene powders are of low molecular weights, i.e., from about 1,000 to 3,500; polypropylene powders having higher molecular weights, i.e., from 120,000 to 350,000 are used. A particularly preferred product is a denture adhesive powder containing about 10% by weight of a cationic copolymer of acrylamide with β-methacryloyloxyethyltrimethyl ammonium methyl sulfate; about 40% by weight of sodium carboxymethyl cellulose; and about 50% by weight of a powdered polyethylene polymer having an average molecular weight of about 2,000 or about 50% by weight of a powdered polypropylene having an average molecular weight of about 140,000.

DESCRIPTION OF THE INVENTION

This invention relates to anhydrous powder and cream preparations which contain a powdered polyethylene or a powdered polypropylene polymer to provide improved wettability characteristics.

The powdered polyethylene polymers suitable for use in the practice of this invention have an average molecular weight ranging from about 1,000 to 3,000, preferably from about 2,000 to 2,500, and a particle size of less than about 422 microns, preferably between about 74 to 149 microns. The particle size may also be stated in terms of the mesh size, i.e., not larger than 40 mesh, preferably between about 100 to 200 mesh. Powdered polyethylene polymers having an average molecular weight of about 2,000 and a particle size of about 74 microns (200 mesh) are especially preferred.

As representative of polyethylene polymers falling into the above-described category, there may be mentioned the waxy reaction products of ethylene with isopropanol, produced according to the processes described in U.S. Pat. Nos. 2,504,400, 2,712,534, and 2,683,141, wherein there is obtained a telomer product having the formula below, with n being 3 to 150:

    CH.sub.3 (C.sub.2 H.sub.4).sub.n C(OH)(CH.sub.3).sub.2

Low molecular weight polymers obtained in this manner are subjected to a pulverizing after-treatment, using a cryogenicpulverizing process, if necessary, to obtain a powdered polyethylene product of the desired particle size.

As examples of commercially available powdered polyethylene products suitable for use in this invention, there may be mentioned those sold by Allied Chemical Company, Morristown, N.J., under the name A-C Polyethylene 6A, A-C Polyethylene 8A, A-C Polyethylene 9A, A-C Polyethylene 6AF, A-C Polyethylene 8AF, and A-C Polyethylene 9AF. Similarly, powdered polyethylene products sold by United States Industries, Park Avenue, N.Y. 10017, as their Microthene series are also suitable.

Powdered polypropylene polymers suitable for use in the practice of this invention have an average molecular weight ranging from about 120,000 to 350,000, preferably about 120,000 to 160,000, and a particle size of less than about 422 microns, preferably between about 74 to 149 microns. Powdered polypropylene polymers having an average molecular weight of about 140,000 and a particle size of about 74 microns are especially preferred. As representative of polypropylene polymers falling into the above-described category, there may be mentioned polypropylene homopolymers prepared by the various polymerization techniques described in Encyclopedia of Chemical Technology, Vol. 14: pages 292-296, 1967, John Wiley & Sons, Inc., i.e., using a Ziegler-Natta catalyst and controlling the molecular weight in order to achieve the desired molecular weight. The polypropylene polymer obtained in pulverized to obtain a powdered material having a particle size suitable for use in the practice of this invention.

As an example of commercially available powdered polypropylene homopolymers which improve the water-wettability of powders and creams according to the teachings of this invention, there may be mentioned those sold by Hercules, Inc., Wilmington, Del., as the Hercoflat series.

The above-mentioned powdered polyethylene or powdered polypropylene, when incorporated into various anhydrous powder and cream formulations, has been found to impart vastly superior wettability characteristics to final products when they are wet with water. The exact reason for this improvement is not thoroughly understood, but is thought to possibly involve the coating of the individual polyethylene particles with one or more hydrophilic ingredients in the anhydrous powder or cream, thus affording improved accessibility of hydrophilic surfaces to the wetting fluid.

Representative anhydrous powder and cream formulations which are substantially improved by the addition of the above-described polyethylene or polypropylene powders include denture adhesives, dentifrices, vaginal powder sprays, and similar cosmetic and drug products. Superior wettability characteristics are obtained in these anhydrous cosmetic and drug products by the addition of about 20% - 60% by weight, preferably about 20% - 55% by weight, based on the weight of the total formulation, of the polyethylene or polypropylene powders, according to the teaching of this invention.

As an example of a product which is particularly improved by the incorporation of the aforementioned polyethylene or polypropylene powders, there may be mentioned a denture adhesive powder formulated to contain, as the adhesive, a mixture of a cationic polymeric component and an anionic natural or synthetic component which, when applied to dentures and exposed to moisture, develops adhesive properties. Such a denture adhesive product is described in U.S. application Ser. No. 243,816, filed Apr. 13, 1972, now U.S. Pat. No. 3,833,518, and in U.S. application Ser. No. 476,622, filed June 5, 1973, now U.S. Pat. No. 3,868,340. In the denture adhesive described in aforementioned patent applications, the cationic polymeric component may include one or more of the following polymeric components:

1. copolymers of an acrylamide having the formula: ##EQU1## wherein R₁ is methyl or hydrogen; and R₂, R₃, and R₄ are each hydrogen or alkyl, with vinyl quaternary ammonium salts including trialkylaminoalkyl acrylate salts, trialkylaminoalkyl methacrylate salts, and vinyloxyalkyltrialkylammonium salts; wherein the alkyl groups are 1 to 7 carbon lower alkyl, preferably 1 to 3 carbon lower alkyl;

2. copolymers of an acrylamide having the Formula (I) above with vinyl and alkyl-substituted vinyl pyridinium salts including 2-vinyl pyridinium salts, 4-vinyl pyridinium salts, 2-alkyl-5-vinyl pyridinium salts, and 2-vinyl-5-alkyl pyridinium salts, wherein the alkyl groups are 1 to 7 carbon lower alkyl, preferably 1 to 3 carbon lower alkyl.

As the quaternary-forming salts in (1) and (2) above there may be mentioned such non-toxic, quaternary forming salts as alkyliodide, alkylchloride, alkylbromide, and alkyl sulfate salts wherein the alkyl group is a lower alkyl group containing 1 to 7 carbon atoms, preferably 1 to 3 carbon atoms. Methyl sulfate salts are particularly preferred. Copolymers of substituted and unsubstituted acrylamide in (1) and (2) above are described in U.S. Pat. Nos. 3,336,269, 3,336,270, and 3,509,113. They are prepared, as described in these last mentioned patents, by a solution polymerization process, wherein an acrylamide monomer having the formula I above and, optionally, an ethylenically unsaturated comonomer, are dissolved in a special solvent (either an acetone-water mixture or an acetone-tertiary-butanol-water mixture) and polymerized to yield a polymeric product in the form of relatively unswollen, hard, non-tacky granules which can be readily isolated from the polymerization reaction by simple filteration, since the polymeric products are not soluble in the polymerization solvent. The polymerization is carried out in the substantial absence of air and the use of a polymerization initiator is recommended. The polymerization temperature is dependent upon the particular initiator used in the system. The concentrations of solvent and the monomer in the polymerization mixture is critical: for the monomers, 5% - 50% (preferably 20% - 35%) by weight, based on the weight of the polymerization reaction mixture is recommended; for the acetone-water mixture solvent, 30% - 70% (preferably 35% - 50%) is used; and for the acetone-tertiary butanol-water mixture solvent, 5% - 65% (preferably 30% - 50%) is recommended, with the amount of tertiary butanol in this last solvent being 5% - 65% (preferably 30% - 50%) by weight, based on the weight of the solvent mixture.

As is usual for polymerization reactions, the molecular weight of the polymers obtained varies directly with the monomer concentration used in the initial reaction mixture. Monomer concentration should be from 15% - 50%, preferably 20% - 35% by weight of the total polymerization reaction mixture if high molecular weight polymers are desired. Monomer concentrations above 50% yield polymeric products having undesirably large, sticky gel particles. For low molecular weight polymers, monomer concentrations below 10% must be used. However, concentrations below 4% - 5% are impractical, since a suspension instead of the desired precipitate of the polymer is obtained.

By selecting suitable concentrations of ingredients and polymerization conditions as described in U.S. Pat. Nos. 3,336,269, 3,336,270, and 3,509,113, it has been found to be possible to obtain cationic polymers and copolymers in the form of finely divided powders having molecular weights of from 5 million to 10 million, which are suitable for use as a cationic ingredient in the denture adhesive of this invention. These polymers and copolymers are soluble in warm or cold water and produce clear solutions having viscosities of from 700 to 1800 centipoises, as measured in a 1% aqueous solution of the polymer, at 25°C with a standard Brookfield LVF Viscometer.

Among the above-described types of cationic polymeric materials, the following have been found to be particularly suitable for use in the denture adhesive of this invention:

1. copolymers of acrylamide with vinyl quaternary ammonium salts including trialkylaminoalkyl acrylate salts, trialkylaminoalkyl methacrylate salts, and vinyloxyalkyltrialkylammonium salts, wherein the alkyl groups are 1 to 7 carbon lower alkyl, preferably 1 to 3 carbon lower alkyl; and

2. copolymers of acrylamide with vinyl and alkyl-substituted vinyl pyridinium salts including 2-vinyl pyridinium salts, 4-vinyl pyridinium salts, 2-alkyl-5-vinyl pyridinium salts, and 2-vinyl-5-alkyl pyridinium salts, wherein the alkyl groups are 1 to 7 carbon lower alkyl, preferably 1 to 3 carbon lower alkyl.

As typical trialkyl aminoalkyl acrylate salt monomers there may be mentioned acryloyloxymethyltrimethyl ammonium methylsulfate; 2-acryloyloxyethyltrimethyl ammonium methylsulfate; 3-acryloyloxypropyltrimethyl ammonium methylsulfate; and acryloyloxymethyltriethyl ammonium ethylsulfate.

As typical trialkylaminoalkyl methacrylate salt monomers there may be mentioned methacryloyloxymethyltrimethyl ammonium methylsulfate; 2-methacryloyloxyethyltrimethyl ammonium methylsulfate; 2-methacryloyloxyethyltriethyl ammonium ethylsulfate; and 3-methacryloyloxypropyltrimethyl ammonium methylsulfate.

As typical vinyloxyalkyltrialkylammonium salt monomers there may be mentioned 2-vinyloxyethyltrimethyl ammonium methylsulfate; 3-vinyloxypropyltrimethyl ammonium methylsulfate; and vinyloxymethyltrimethyl ammonium methylsulfate.

As typical vinyl pyridinium salts there may be mentioned 1-methyl-2-vinyl pyridinium methylsulfate; 1-ethyl-4-vinyl pyridinium ethyl sulfate; 1,2-dimethyl-5-vinyl pyridinium methylsulfate; 1-methyl-2-vinyl-5-ethyl pyridinium methylsulfate; and 1-methyl-2-vinyl-5-propyl-pyridinium methylsulfate.

The amount of each monomeric component in the above-mentioned cationic copolymers utilized in the denture adhesive of the invention may be varied within certain ranges to provide a product suitable for use in the denture adhesive of this invention. Generally, from 50% to 90% by weight of the acrylamide type monomer, preferably 63% to 85%, most preferably 85% by weight, based on the total weight of the copolymer, is used. Correspondingly, from 10% to 50% by weight of the vinyl quaternary ammonium salt (or the vinyl pyridinium salt) comonomer, preferably 15% to 37%, most preferably 15% by weight, based on the total weight of the copolymer, is used.

The preferred cationic component for the denture adhesive of this invention is a copolymer of acrylamide with one of the above-mentioned vinyl quaternary ammonium salts.

In a most preferred embodiment of this invention, the cationic component comprises 85% by weight of acrylamide and 15% by weight of a trialkylaminoalkyl methacrylate salt having 1 to 3 carbon atoms in the alkyl group, i.e., 2-methacryloyloxyethyltrimethyl ammonium methylsulfate, based on the total weight of the copolymer.

As the anionic ingredient of the denture adhesive of this invention, there may be used one or more gums of the natural variety selected from the group gum karaya, gum arabic, gum Shiraz (gum ghatti), gum tragacanth, pectin and salts thereof (pectinates), algin and salts thereof, (alginates) and the like, which are anionic in character.

Among the suitable anionic materials described above, one or more of the following gums has been found to be especially effective in the denture adhesive of this invention: gum karaya, gum arabic and gum Shiraz. Gum arabic is particularly preferred.

An improved denture adhesive powder containing the above-described ingredients, together with polyethylene or polypropylene powder according to the teachings of this invention is formulated to contain from about 40% to 60% by weight, based on the weight of the total formulation, of the powdered polyethylene or powdered polypropylene; from about 5% to 55% by weight, of at least one of the above-described cationic polymeric materials; and from about 5% to 55% by weight, of at least one of the above-described anionic gums. Preferred products contain from about 45% - 55% by weight, based on the weight of the total formulation of the polyethylene or polypropylene powder; about 5% - 20% by weight, of at least one of the cationic polymeric materials; and from about 20% - 50% be weight, of at least one of the anionic gums. A most preferred product is formulated to contain about 50% by weight, based on the weight of the total formulation of the polyethylene or polypropylene powder, about 10% by weight, of at least one cationic polymeric material, and about 40% by weight, of at least one anionic gum.

Typical dentifrice powder formulations which may be improved by the incorporation of the above-described powdered polyethylene or powdered polypropylene, according to the practice of this invention, are formulated to contain an abrasive material, such as dicalcium phosphate dihydrate or precipitated calcium carbonate, a soap or detergent ingredient, flavors, sweeteners and excipients. Such representative dentifrice powders are described in Remington's Pharmaceutical Sciences, pages 1785-1786, 13th Edition, Mack Publishing Co., Easton, Pa., 1965. In order to obtain improved wettability, according to the teachings of this invention, the powdered polyethylene or powdered polypropylene is incorporated into the dentifrice powder formulation at a level of from about 20% - 60% by weight, based on the total weight of the formulation, preferably about 20% - 50% by weight, most preferably about 45% by weight.

As an example of an anhydrous dentifrice paste, there may be mentioned the toothpaste formulation of U.S. Pat. No. 3,574,824. Improved wettability of the aforementioned anhydrous toothpaste is obtained by the incorporation of the powdered polyethylene or powdered polypropylene, according to the practice of this invention. A typical improved anhydrous toothpaste formulation of this type contains a mineral oil ingredient; a polyethylene glycol composition; a nonionic emulsifier such as Atmos 300 (Atlas Chemical Industries); a binding agent such as polyvinylpyrrolidone; mannitol or inositol; an abrasive, and coloring agents; sweeteners, and the usual excipients, together with from about 20% - 60% by weight, based on the weight of the total formulation, of powdered polyethylene or powdered polypropylene, as described above. Preferred anhydrous dentifrice pastes contain about 20% - 50% by weight, based on the weight of the total formulation, of polyethylene or polypropylene powders; and a most preferred product contains about 20% by weight, based on the total weight of the formulation, of polyethylene or polypropylene powder, to improve wettability characteristics of the anhydrous dentifrice paste. Such modified anhydrous toothpaste formulations demonstrate more thorough cleansing power when applied to the teeth, since wettability characteristics have been greatly improved.

Representative vaginal spray powders which may be improved by the addition of the polyethylene or polypropylene powder according to the practice of this invention generally contain solid ingredients including a lubricant, such as isopropyl palmitate, and talc, together with the desired liquid fragrances and an anhydrous alcohol solvent. Propellants are added as the formulation is placed into the spray container. In order to improve the wettability of vaginal sprays of this type, from about 20% - 60% by weight, based on the total weight of solids in the formulation, of powdered polyethylene or powdered polypropylene is added to the formulation. Preferred products contain from about 20% - 60% by weight of powdered polyethylene or polypropylene, based on the total weight of solids. Particularly preferred products are formulated to contain about 23% by weight of powdered polymer, based on the total weight of solids, in order to provide superior wettability characteristics to the vaginal spray product.

Obviously, many other anhydrous powder and cream preparations in the cosmetic, dental and drug field, other than those specifically mentioned above, could be improved by the addition of the powdered polyethylene or polypropylene according to the practice of this invention.

To further illustrate the invention, the following examples are given:

EXAMPLE 1 Preparation of Improved Denture Adhesive Powder

In a Hobart mixer, add 1,450 grams of a gum tragacanth and 6.25 grams of peppermint oil, USP. Mix until the ingredients assume a crumbly, dry character and pass through a No. 20 mesh screen. Into a separate blender, add 500 grams of a copolymer of 85% by weight acrylamide with 15% by weight acryloyloxymethyltrimethyl ammonium methyl sulfate; 500 grams of gum Shiraz; and 2543 grams of powdered polyethylene having an average molecular weight of 2000 and having particle size such that 99.5% of the polyethylene powder passes through a 60 mesh screen. Add in the mixed gum and peppermint oil from the Hobart mixer. Mix all ingredients for 20 minutes or until a uniform blend is obtained. Add in 0.25 grams of F D & C Red No. 3 Aluminum Lake and mix to visual uniformity.

EXAMPLE 2 Improved Denture Adhesive Powder

A denture adhesive powder is prepared according to the procedure, Example 1, from the following ingredients:

    Copolymer of acrylamide and                                                    2-Methacryloyloxyethyltrimethyl                                                Ammonium methyl sulfate                                                                               500     grams                                           Gum arabic             2000    grams                                           Spearmint oil, USP     6.25    grams                                           Polyethylene (60 mesh) 2550    grams                                           F D & C Aluminium Lake .25     grams                                      

EXAMPLE 3 Preparation of Denture Adhesive Powder

A denture adhesive powder is prepared according to the procedure of Example 1, from the following ingredients:

    Copolymer of acrylamide and                                                    β-methylacryloyloxyethyltrimethyl                                         ammonium methyl sulfate                                                                               9.0     pounds                                          Gum Karya              44.5    pounds                                          Gum Shiraz             46.4    pounds                                          Polypropylene Powder (60 mesh)                                                                        45.0    pounds                                          Spearmint Oil          0.05    pounds                                          Peppermint Oil         0.05    pounds                                     

The peppermint and spearmint oils are well dispersed in the gum karaya and gum Shiraz. The whole is then mixed for about 15 minutes, after which the copolymer is added and the batch mixed for an additional 15 minutes. The polypropylene is then added and mixing continued for a final 15 minutes.

EXAMPLE 4 Preparation of Improved Powdered Dentifrice

50.0 Grams of calcium carbonate (precipitated) is placed in a powder mixing device with 47.8 grams of powdered polyethylene having an average molecular weight of about 2000 and a particle size of approximately 60 mesh. To this is added 1 gram of flavor oil and 1.2 grams of sodium lauryl sulfate. The whole is mixed for about 15 minutes to 30 minutes, to visual uniformity.

EXAMPLE 5 Preparation of Improved Anhydrous Toothpaste Formulation

255 grams of a mixture polyethylene glycols having average molecular weights of 550, 600, and 4,000, and 50 grams of a propylene glycol bodying agent are mixed and melted at 65°-70°C. Heat is discontinued and 10 grams of polyvinylpyrrolidone is added to the heated mixture which is stirred vigorously to form a uniform slurry (A). In a separate steamjacketed mixer, 100 grams of mineral oil, 40 grams of a petrolatum bodying agent and 2 grams of Atmos 300 emulsifier (Atlas Chemical Industries) are mixed and heated to a temperature of 50°C. The slurry (A) is added to the ingredients in the steam-jacketed mixer. The following remaining ingredients, after screening (20 mesh screen) are then added to the mixer: 20 grams of sodium lauryl sulfate detergent, 257 grams of hydrated alumina abrasive, 30 grams of aluminum silicate abrasive, 26 grams of mannitol, 10 grams of titanuim dioxide color, and 76 grams of synthetic sweetener. All ingredients are mixed for 20-25 minutes, after which heat is discontinued and the mixture cooled to 30°C. 200 grams of powdered polypropylene having an average molecular weight of about 140,000 and a particle size of approximately 200 mesh, is added together with 20 grams of flavor, and the whole is mixed for an additional 20-25 minutes.

EXAMPLE 6 Preparation of Improved Vaginal Spray Powder

Add 0.5 grams of the isopropyl palmitate and 2.10 grams of a powdered polyethylene having an average molecular weight of about 2000 and a particle size of approximately 200 mesh to 2.5 grams of anhydrous alcohol and mix thoroughly. Add .2 grams of fragrance and blend with other ingredients. Weight 5 grams of blended ingredients into an aerosol container, add 8.5 grams of talc and pressure fill with 88.2 grams of propellant (40:60 mixture of Propellant 12 and Propellant 114). 

Having thus described our invention, We claim:
 1. A denture adhesive powder having superior wettability characteristics comprises a substantially anhydrous mixture of nontoxic, adhesive ingredients and from about 40% to about 60% by weight, based on the total weight of the denture adhesive ingredients of a powdered polymeric material having an average particle size of less than about 422 microns, said polymeric material being selected from the group consisting of powdered polyethylene having an average molecular weight ranging from about 1000 to about 3500 and powdered polypropylene having an average molecular weight ranging from about 120,000 to about 350,000, said denture adhesive ingredients comprising:A. from about 5% to about 55% by weight, based on the total weight of the denture adhesive ingredients of at least one cationic polymeric material selected from the group consisting of1. a copolymer of an acrylamide having the formula: ##EQU2## wherein R₁ is methyl or hydrogen; and R₂, R₃, and R₄ are each hydrogen or 1 to 7 carbon lower alkyl, with a vinyl quaternary ammonium salt selected from the group consisting of trialkylaminoalkyl acrylate salts, trialkylaminoalkyl methacrylate salts, and vinyloxyalkyltrialkylammonium salts, wherein the alkyl group contains from 1 to 7 carbon atoms; and
 2. 2. a copolymer of an acrylamide having the formula (I) above with a vinyl or alkyl-substituted vinyl pyridinum salt, wherein the alkyl group is 1 to 7 carbon lower alkyl; andB. from about 5% to about 55% by weight, based on the total weight of the denture adhesive, of at least one anionic gum selected from the group consisting of gum karaya, gum arabic, gum Shiraz, gum tragacanth, pectin, pectinates, algin and alginates.
 2. A denture adhesive according to claim 1 wherein the powdered polymeric material which provides the superior wettability characteristics is present in an amount of from about 45% to about 55% by weight, based on the total weight of the denture adhesive ingredients; said powdered polymeric material having an average particle size of between about 74 to 149 microns and being selected from the group consisting of a powdered polyethylene having a molecular weight of from about 2000 to about 2500, and powdered polypropylene having an average molecular weight of from about 120,000 to about 160,000.
 3. A denture adhesive powder according to claim 1 wherein the adhesive ingredients comprise:A. from about 5% to about 20% by weight, based on the total weight of the denture adhesive ingredients, of at least one cationic copolymer of acrylamide with a vinyl quaternary ammonium salt selected from the group consisting of trialkylaminoalkyl acrylate salts, trialkylaminoalkyl methacrylate salts, and vinyloxyalkyltrialkylammonium salts wherein the alkyl group contains from 1 to 3 carbon atoms; and B. from about 20% to about 50% by weight, based on the total weight of the denture adhesive ingredients, of at least one anionic gum selected from the group consisting of gum karaya and gum arabic.
 4. A denture adhesive powder according to claim 3 comprising:A. about 10% by weight, based on the total weight of the denture adhesive ingredients, of a cationic copolymer of acrylamide with 2-methacryloyloxyethyltrimethyl ammonium methyl sulfate; B. about 40% by weight of gum arabic and C. about 50% by weight of a powdered polyethylene having an average molecular weight of about 2000, and an average particle size of about 74 microns. 